In practical situations, the change of attribute values can lead to a certain covering change in-covering- information system, and it is time-consuming to compute lower and upper approximations of sets with the non-incremental approaches at this moment. Thus, matrix-based incremental approaches are proposed to calculate lower and upper approximations of sets in dynamic covering information systems caused by variations of attribute values. Firstly, incremental approaches are proposed to compute two kinds of characteristic matrx of dynamic covering. Then, incremental algorithms are proposed to compute lower and upper approximations of sets based on the given two kinds of characteristic matrix, respectively, and an example is used to illustrate the calculation process of the proposed algorithms. Finally, simulation results verify the effectiveness of the proposed algorithms.